Rapid photographic development system

ABSTRACT

A rapid photographic developing process for color photography which comprises passing a latent-image-bearing film or print sequentially through a developer bath, a stop bath, a bleach-fix bath, a water bath, and a stabilizer bath. The components of the baths are balanced so that the process may be carried out at temperatures of 85* to 95* F. or higher to obtain rapid and consistently good results.

United States Patent Inventor John A. Kosta Dayton, Ohio Appl. No. 793,509

Filed Jan. 23, 1969 Patented Nov. 16, 1971 Assignee Technology Incorporated Dayton, Ohio RAPID PHOTOGRAPI'IIC DEVELOPMENT SYSTEM 10 Claims, 1 Drawing Fig.

U.S. Cl 96/22, 96/55, 96/48 QP Int. Cl .r G03c 5/50, G03c 5/24 Field of Search 96/22, 48, 55

[56] References Cited UNITED STATES PATENTS 1,907,252 5/1933 Debrie 96/48 2,04 l .478 5/1936 Niederle 96/48 2,945,760 7/l960 Ostergaard, Jr. 96/48 3,372,030 3/1968 Jacobson 96/55 Primary ExaminerNorman G. Torchin Assistant ExaminerAlfonso T. Suro Pico Attorney-William R. .lacox ABSTRACT: A rapid photographic developing process for color photography which comprises passing a latent-image bearing film or print sequentially through a developer bath, a stop bath. a bleach-fix bath, a water bath, and a stabilizer bath. The components of the baths are balanced so that the process may be carried out at temperatures of to F. or higher to obtain rapid and consistently good results.

RAPID PHOTOGRAPI-IIC DEVELOPMENT SYSTEM BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to improvements in a processing complex or system comprising the passage of a photosensitive film or paper through a sequence of solutions or baths to develop the image. The system is particularly adaptable but not necessarily limited to color photography.

2. Description of the Prior Art While the photographic art in general and the art of color photography in particular have more than kept pace with the general advancement of the arts and sciences, the image development technology has lagged, particularly with regard to the time required for the processing of color photographs. While it has been known that increases in temperatures of the system will increase the processing rate of a particular developer, conventional systems have been limited to temperatures of no higher than 75 F. to avoid the chemical stains or fogging which have occurred where the systems have been operated above this temperature level. In addition to the limitations on the reaction rates, the nature of the chemical reactions heretofore involved in photographic development and particularly in development of colored photographs has been such that the residual effects thereof at the various stages in the process have required a relatively large number of separate steps and baths to wash the image-bearing film between certain of the successive steps. The need for such a large number of baths has also necessarily increased the time involved in the total processing as well as the expenses incurred for the manpower and equipment to accomplish them. Moreover, the prior art systems have involved so many processing parameters, the criticality of which required their careful control that the costs of the equipment and the manpower were thereby further increased; and this problem has only been further enhanced by the complications introduced in the development of color photographs. Another result of this criticality has been that it has, prior to the present invention, been economically impractical for the amateur photographer or hobbyist to develop his own color photographs.

SUMMARY it is accordingly an object of the present invention to provide a photographic development system, particularly adaptable to color photography, for recovering a latent photographic image from a sensitized silver halide emulsion in a substantially reduced amount of time.

it is a further object of the invention to provide such a processing system which will eliminate certain steps required by the prior art as well as the time and equipment required to perform such steps.

Yet another object of the invention is to provide such a developing system wherein the chemical reaction rates may be increased by operating the system at increased temperatures without at the same time encountering uncontrollable stain or fog of the type that has heretofore been encountered where reaction temperatures have been raised.

A further object of the invention is to provide a processing system for automatic processing equipment which yields fast and highly consistent results.

Yet another object of the invention is to provide a system that may be used in the simplest of processing equipment over wide time and temperature limits and wherein the noncriticality of the processing parameters are such that the system may be carried out by an amateur in a home darkroom.

These and other objects and advantages of the invention which will appear from a reading of the following disclosure are achieved by the provision of a specific developer solution and a specific bleach-fix solution which may be sequentially employed in a conventional or simplified conventional developing system wherein the combined effect of the two solutions so employed is such that high quality color photographic prints can be consistently and easily obtained over a temperature range the breadth of which is such that the system is amenable to any form of equipment and a great divergence of ambient conditions and the upper limits of which is such that the reaction rates may be increased substantially to reduce the time involved in the process.

For example, a conventional development system comprises a development step requiring 7 minutes, a stop-bath treatment requiring 1 minutes, a washing step requiring 2 minutes, a bleaching step requiring 2 minutes, a washing step requiring 2 minutes, a fixing stage requiring from 2 to 4 minutes, a further washing step requiring 4 minutes and a final stabilizing step requiring from 2 to 3 minutes for a total of eight baths and a minimum of 25 minutes. The within system however requires only a development step, a stopping stage, a bleach-fixing stage, a single wash and a final stabilizing step for a total of only five baths. Moreover, the chemistry of the solutions of the within invention is such that the reactions may be carried out at temperatures of F. or above.

The developer bath according to the present invention is an aqueous slution, each liter of which may contain from 0.2 to 10 grams of preservatives or antioxidants such as sodium sulfite, hydroxylamine, ascorbic acid, the tetronimides or the like, from 10 to grams of an alkali such as an alkali metal phosphate, carbonate, borate or hydroxide or a mixture of such, from 3 to 10 grams of a paraphenylene-diamine derivative developing agent and only a very small amount; viz from 0.3 to 1.0 gram of potassium bromide or sodium bromide and a very small amount, on the order of 0.002 gram of potassium iodide. The developer solution may also contain conventional additional ingredients known to the prior art such as accelerators, sequestering agents, wetting agents, hardeners, and the like.

This developing solution according to the present invention is then employed as the first step of a five-step sequence, the second step of which comprises a stop bath. While a water wash may be used in lieu of the stop bath, the stop bath, particularly in the case of automatic processing machinery such as roller transport apparatuses is preferred. One such bath particularly adaptable for use in connection with the specific developer solution above described is composed of from 4 to 20 grams of potassium metabisulfite in l liter of water wherein the relative acidity of the solution is adjusted to have a pH value of from 4.00 to 6.50. To this stop bath also may be added certain additional conventional ingredients such as acetic acid, phosphates, and the like for the purposes of buffering. Other silver halide solvents such as sodium thiosulfate, potassium thiocyanate, ammonium thiosulfate and the like may be used to fix the silver halide at this stage of the process.

Following the stop bath treatment, the film is then passed through or placed in the novel bleach-fix bath each liter of which, according to the within invention, is composed of a major proportifn; i.e., from 40 to 300 grams of a silver halide solvent such as ammonium thiosulfate or sodium thiosulfate, from 6 to 50 grams of an iron salt of ethylenediamine tetraacetic acid and from 4 to 40 grams of a sequestering agent such as ethylenediamine tetraacetic acid, the sodium or potassium salts of ethylenediamine tetraacetic acid, trisodium or other phosphates or any of the chelating agents of that class set forth above. For improved storage characteristics, buffering latitude or acceleration in the manner known to the art, the bleach-fix bath may include various additional compounds.

The bleach-fix stage is then followed by a water wash and immersion in a stabilizer liquid such as a conventional aqueous formaldehyde solution which may contain other well known ingredients such as optical whitening agents, buffers, sequestering agents and wetting agents.

All of the above-described baths are arranged in a manner to accommodate a sequential immersion of the photosensitive film or paper in any of a variety of arrangements that are known to the prior art for accomplishing this purpose such as in the case of strand processing, roller transport processing, drum processing and basket processing, manually or otherwise. Where the developing bath and related solutions are maintained at a temperature of 85 F., stain and fog-free color photographs of high quality can be consistently obtained by exposing the photosensitive film or paper to the developing bath for 1.5 minutes, to the stop bath for 0.5 minute, to the bleach-fix bath for from I to 2 minutes, to the subsequent wash for 2 minutes and to the stabilizing bath for 1 minute representing a total of from 6 to 7 minutes to the point at which a fully developed photograph ready for drying is obtained. Where the solutions are maintained and the development process is carried out at a temperature of 95 F. on the other hand, the same quality results are obtainable even though the exposure of the photograph is as low as 50 seconds to the developer solution, 20 seconds to the stop bath, 50 seconds to the bleach-fix bath, 90 seconds for the subsequent wash and 50 seconds to the stabilizer representing a total of only 4 minutes and 20 seconds until the finished photograph ready for drying is obtained. On the other hand, and particularly in the case of amateur or hobbyist wherein it might be desired to carry out the developing process at a lower tem perature such as normal room temperature of say 75 F., the same solutions and baths may be employed to obtain the high quality photographs by increasing the immersion times to 4 minutes in the developer, from 2 to 3 minutes in the short-stop bath, from 3% to 4 minutes in the bleach-fix bath, from 6 to 10 minutes in the final wash and from 4 to 6 minutes in the stabilizer.

The chemical condition of the developer and bleach-fix baths employed as described above readily adapts itself for use in automatic processing machines with automatic replenishment reservoir-dispensing systems. In such case the replenishing solutions are the same as the original formulas described above except that the developer should contain not less than from 4 to 10 grams of the developing agent such as the paraphenylenediamine derivative per liter of solution and a higher concentration of alkali to keep the pH value of the solution at from 11 to 12.5. The flexibility of the process afforded by the fact that the time-temperature process parameters are rendered much less critical makes the system particularly adaptable to automatic processing machinery such as strand or roller transport systems in that the sensitized film or paper may be carried at a constant speed through the entire sequence of baths without incurring fogs, stains, undesirable density variations and the like. Thus, for example, highly consistent results are obtainable where the above-described baths and solutions are maintained at a temperature of on the order of 95 F. and the machinery is operated so that the sensitized filrn will be in each of the solutions 1 minute. BRIEF DESCRIPTION OF THE DRAWING The drawing is a diagrammatic elevational view of a rollertransport color photographic processing apparatus embodying the features ofthe present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a system according to the invention particularly adapted for tray or basket color photographic processing, specific baths or chemical solutions for the respective steps in the process have been found to be composed as follows.

Each liter of the developer solution contains 1.0 gram of sodium hexametaphosphate as a sequestering agent, 5.7 grams of sodium sulfite as an antioxidant, 0.6 gram of potassium bromide as a restrainer, l.2 gram of hydroxylamine hydrochloride as an additional antioxidant, 6.0 grams of paraphenylenediamine derivative; e.g., that sold by the G.A.F. Corporation of New York, New York under its proprietary designation S-S" as a developing agent and approximately 50 grams of potassium carbonate. Sufficient water is added to make 1 liter of solution, the acidity of which is then adjusted with a conventional adjuster such as sodium hydroxide to yield a pH value within the range offrom 10.0 to l 1.0.

The stop bath to be employed immediately following immersion in the above-described developer solution is then composed of 100 grams of ammonium thiosulfate, l0 grams of sodium sulfite, l5 grams of potassium metabisulfite, l0 grams of sodium acetate and sufficient water to make a l-liter aqueous solution the acidity of which is then adjusted by the addition of acetic acid to achieve a pH value within the range of from 5.0 to 6.0.

A novel bleach-fix bath according to the within invention is then composed of 120 grams of ammonium thiosulfate as a halide solvent, 25 grams of an iron donor such as sodium ferric salt of ethylenediamine tetraacetic acid; e.g., that sold by Geigy lndustrial Chemical Division of Geigy Chemical Corporation, Ardsley, New york 10502, under its proprietary designation Sequestrene Na Fe, 14.0 grams of another sodium salt of ethylenediamine tetraacetic acid; e.g., disodium ethylenediamine tetraacetic acid, sold by Geigy lndustrial Chemical Division of Geigy Corporation, Ardsley, New york 10502, under its proprietary designation Sequestrene Na 2," approximately 2.0 grams of potassium carbonate as a buffer to adjust the pH value to within a range of from 6.4 to 7.0 after the addition of sufficient water to complete l liter of the aqueous solution.

Each liter of the stabilizer solution representing the last stage or bath in the system is composed of from 15 to 40 milliliters of a 37 percent aqueous formaldehyde solution, 4.0 grams of a tetrasodium salt of ethylenediamine tetraacetic acid such as that sold by the Geigy Industrial Chemical Division of Geigy Chemical Corporation, Ardsley, New York 10502, under the proprietary designation Sequestrene Na 4," 2.0 grams ofa buffer such as disodium phosphate and sufficient additional amounts of monosodium phosphate as an adjusting buffer to bring the acidity of the solution to a pH value within the range of from 6.0 to 7.0.

The above solutions are employed by placing them in sequentially arranged trays or reservoirs, and the photographically sensitized paper or film is then sequentially immersed in the successive baths for the prescribed period of time which, as above indicated, will vary with the temperature of the solutions. Where the processing temperatures is F. the paper should be first immersed in the developer bath for 1 minute and 30 seconds and is then preferably removed and allowed to drain for 15 seconds before it is immersed in the shortstop bath for 55 seconds. The print is then removed, drained for 5 seconds and placed in the bleach-fix bath for 1 minute and 5 seconds and is then redrained for l0 seconds before being placed in a water bath for 4 minutes and then in the stabilizing bath for 2 minutes. After the print has been in the bleach-fix solution for 10 seconds, the room lights may be turned on: and, after it has been washed for 30 seconds, preferably in running water, the print may be evaluated for both color balance and exposure. The print thus processed may then be dried by any customary method so long as the drying temperature does not exceed 250 F. If the processing temperature of the baths is raised to and maintained at F. the total time for each processing step, including the draining and transfer times is reduced to 1 minute for the developer, 45 seconds for the short stop, 1 minute for the bleach-fix, 2 minutes for the water wash and 30 seconds for the stabilizer. At a system temperature of 75 F., on the other hand, the developer time is 4 minutes, the short stop requires 2 minutes, the bleach-fix 3 minutes and 30 seconds, the wash 6 minutes and the stabilizer 4 minutes.

At 85 F. processing temperatures for consistent results, the developer bath is preferably maintained at a temperature of within one-half degree, the short stop and bleach-fix baths at a temperature of within 2 of stated temperature. While the temperature tolerances are increased at 75 F. processing temperatures to l for the developer, 3 for the short stop and bleach-fix and 5 for the wash and stabilizer, an increase in the processing temperature to 95 F. reduces the tolerances to one-fourth of a degree for the developer, l for the short stop and bleach-fix and 2 for the wash and stabilizer.

Since the solutions according to the within invention are all aqueous solutions, they may be conveniently packaged and sold in concentrated form in kits for example to which the amateur or occasional photographic practitioner can simply add water and employ baskets or trays such as are customarily employed in the processing of black and white prints. On the other hand, the above-described solutions can be employed in connection with conventional processing machinery such as drum developers and strand processing equipment. More importantly, it has been found that the processing solutions according to the within invention may also be employed in connection with a roller-transport processing system of the type which has heretofore been employed for the development or processing of black and white films or negatives but could not beused for color photography.

Such a roller-transport apparatus is shown in the drawing to comprise the housing at the forward end of which is positioned the loading table 11 and at the rear end of which is the dispensing chute 12. The unit is divided generally into the processing section 13 and the drying section 14, the latter of which embodies a conventional heating element or a bank of heating elements such as electrical resistance heaters 15 and a blower 16 or forcing air over or through the heater and over the processed photographic film or print which is carried through the drying section by the gear-driven contact rollers 17. Positioned within the processing section of the device are the sequentially arranged developing chamber or reservoir 18, the short stop reservoir 19, the bleach-fix chamber 20, the washing section 21, and the stabilizing bath 22. Opposed pairs of tangentially contacting transport rollers 23 are rotatably mounted at closely spaced points throughout a serpentine pattern leading to and from the bottom of each of the baths or reservoirs 18 through 22; and, all of the transport rollers are rotatably driven as by a gear train suitably associated with a power source (not shown) so that the film or print paper to be processed may be fed from the loading table 11 into the bite of the first pair of transport rollers and then carried by successive contacts with subsequent pairs of rollers through the consecutive baths. To maintain the solutions within the reservoirs each of the troughs or baths may be associated with a replenishing pump represented diagrammatically by the numbers 24 through 28, each of which is also in fluid communication with a supply source of the solution and can be controlled by conventional means such as float-operated valves and switches to introduce additional solution into the respective baths as the solution level therein drops below a predetermined point.

While the solutions employed in the above-described apparatus may be substantially identical to those previously described, it has been found that preferred results are obtained if each liter of the developer solution is modified by raising the amount of sodium sulfite from 5.7 to 6.0 grams, reducing the potassium bromide from 0.6 to 0.5 gram, increasing the hydroxylamine hydrochloride from 1.2 to 1.6 grams, increasing the paraphenylenediamine derivative from 6.0 to 6.5 grams and by adjusting the acidity of the solution to a pH value of 10.8. Similarly it has been found that a slightly modified developer solution is preferably employed in the replenishment of the development bath; and each liter of the replenishing developer solution is preferably composed of 1.0 gram of sodium hexametaphosphate, 6.2 grams of sodium sulfite, 0.6 gram of potassium bromide, 1.6 grams of hydroxylamine hydrochloride, 7.5 grams of the paraphenylenediamine derivative and sufficient sodium hydroxide to adjust the pH of the solution to a value of 12.

Again, in the case of the bleachfix bath, it is preferred that the solution be slightly modified for use in connection with the transport apparatus above described; but it has been found that both the original solution and that used to replenish the bath may be of the same composition. Each liter of the preferred bleach-fix solution for machine use is composed of 120 grams of ammonium thiosulfate, 15.0 grams of the Sequestrene Na Fe, 8.0 grams of the Sequestrene Na 2, 1.0 gram of an additional ethylenediamine tetraacetic acid known as Sequestrene AA," sold under that name by the Geigy industrial Chemical Division of Geigy Chemical Corporation,

Ardsley, New York 10502, and 3.0 grams of disodium phosphate. it has been found that there is no need for modifying the short-stop or stabilizer solutions for use in the roller transport apparatus; and the same composition of such solutions as that set forth above may be so employed. With such nominal empirical adjustments as can be easily made according to preliminary tests and procedures well known to the prior art, the above-described solutions may be employed in connection with the roller transport apparatus for example to make color photographic prints on sensitized print paper such as the Agfa-Gevaert MCN l 1 1 color paper by maintaining the temperature of the baths at 95 F. and so controlling the rotational speed of the print paper transporting rollers that print paper will be immersed in each of the baths for an interval of 60 seconds; i.e., while it is passing through the bath, and to remain in the drying section for an interval of 2 minutes. With the addition of nominal time periods to allow the print to be carried from one bath to another, the combination of the roller transport apparatus and the novel solutions provided by the present invention makes possible for the first time a production of a dry color print in no more than 1 1 minutes.

While the within invention has been described in connection with certain specific embodiments thereof, it is to be understood that the foregoing particularization has been for the purpose of illustration only and does not limit the invention as it is defined in the sub joined claims.

The invention having thus been described, the following is claimed:

1. A rapid color-photographic process for developing an image, present as a latent image on a light-sensitized silver halide photographic emulsion on a film or paper, comprising the sequential steps of:

a. passing the photographic emulsion through an aqueous developer bath, each liter of which includes in solution about 5.7 to 6.0 grams of sodium sulfite, about 1.2't0 1.6 grams of hydroxylamine hydrochloride, about 3 to 10 grams of a paraphenylenediamine developing agent, about 0.3 to 1.0 gram of an antifoggant agent, about 0.002 gram of potassium iodide, and sufficient alkali to adjust the pH to about 10.8;

b. passing the photographic emulsion through a bath selected from the group consisting of a water wash bath and a conventional acidic stop bath;

c. passing the photographic emulsion through an aqueous bleach-fix bath, buffered to a pH of 6.4 to 7.0, each liter ofwhich includes in solution about 120 grams of ammoniurn thiosulfate, about 15 to 50 grams of an iron salt of ethylenediamine tetraacetic acid, and about 4 to 40 grams of an iron sequestering agent;

d. passing the photographic emulsion through a water wash bath;

e. passing the photographic emulsion through a conventional aqueous stabilizer bath; and

f. drying the developed photographic emulsion; wherein the temperature of each bath is maintained at about to F. and wherein the time of passing the film through each bath is about 30 seconds to 2 minutes.

2. The process of claim 1 wherein the antifoggant in the developer bath is chosen from the group consisting of sodium bromide and potassium bromide.

3. The process of claim 1 wherein the bath of step b is a stop bath having a pH value of5.0 to 6.0.

4. The process of claim 1 wherein the iron sequestering agent in the bleach-fix bath is selected from the group consisting of ethylenediamine tetraacetic acid, sodium salts of ethylenediamine tetraacetic acid, potassium salts of ethylenediamine tetraacetic acid, trisodium phosphate, sodium dihydroxyethyl glycinate, nitrilotriacetic acid. trisodium nitrolotriacetate, transl ,2-diaminocyclohexane-tetraacetic acid monohydrate, trisodium hydroxyethylenediamine triacetate, hydroxyethylethylene-diaminetriacetic acid. ethylenediaminedi-(orthohydroxyphenylacetic acid). diethylenetriaminepentaacetic acid, pentasodium diethylenetriaminepentaacetate, diaminoethyl ether tetraacetic acid, and ethyleneglycol bis (aminoethylether) tetraacetic acid.

5. The process of claim 4 wherein the iron sequestering agent is disodium ethylenediamine tetraacetic acid in an amount of 8 or 14 grams per liter ofsolution.

6. The process of claim 1 wherein the antifoggant in the developer bath is potassium bromide in an amount of 0.5 to 0.6 gram per liter of solution.

7. The process of claim 1 wherein the photographic emulsion is passed through the succeeding baths and drying means by roller transport means.

8. A photographic developer bath for developing colored films and prints comprising about 5.7 to 6.0 grams of sodium sulfite about 1.2 to L6 grams of hydroxylaminc hydrochloride, about 3 to ID grams of a paraphenylenediamine developing agent, about 0.03 to L gram of an antifoggant agent, about 0.002 gram of potassium iodide, sufficient water to make the solution I liter in volume and sumcient alkali to adjust the pH to about l0.8.

9. A color photography developer bath for use in replenishing the developer bath of claim 8 when it is used in a roller transport apparatus, consisting of an aqueous solution, each liter of which comprises about 6.2 grams of sodium sulfite, about l.6 grams of hydroxylamine hydrochloride, about 7.5 grams ofa paraphenylenediamine developing agent, about 0.6 gram of an antifoggant agent, and sufficient alkali to adjust the pH to about 12.0.

10. A photographic bleach-fix bath for use in color photographic film and print development consisting of an aqueous solution, each liter of which comprises about grams ammonium thiosulphate, about 15 to 50 grams of an iron salt of ethylenediamine tetraacetic acid, and about 4 to 40 grams of an iron sequestering agent, and sufficient alkali and buffering agents to provide a pH of 6.4 to 7.0. 

2. The process of claim 1 wherein the antifoggant in the developer bath is chosen from the group consisting of sodium bromide and potassium bromide.
 3. The process of claim 1 wherein the bath of step b is a stop bath having a pH value of 5.0 to 6.0.
 4. The process of claim 1 wherein the iron sequestering agent in the bleach-fix bath is selected from the group consisting of ethylenediamine tetraacetic acid, sodium salts of ethylenediamine tetraacetic acid, potassium salts of ethylenediamine tetraacetic acid, trisodium phosphate, sodium dihydroxyethyl glycinate, nitrilotriacetic acid, trisodium nitrolotriacetate, trans-1,2-diaminocyclohexane-tetraacetic acid monohydrate, trisodium hydroxyethylenediamine triacetate, hydroxyethylethylene-diaminetriacetic acid, ethylenediaminedi-(orthohydroxyphenylacetic acid), diethylenetriaminepentaacetic acid, pentasodium diethylenetriaminepentaacetate, diaminoethyl ether tetraacetic acid, and ethyleneglycol bis (aminoethylether) tetraacetic acid.
 5. The process of claim 4 wherein the iron sequestering agent is disodium ethylenediamine tetraacetic acid in an amount of 8 or 14 grams per liter of solution.
 6. The process of claim 1 wherein the antifoggant in the developer bath is potassium bromide in an amount of 0.5 to 0.6 gram per liter of solution.
 7. The process of claim 1 wherein the photographic emulsion is passed through the succeeding baths and drying means by roller transport means.
 8. A photographic developer bath for developing colored films and prints comprising about 5.7 to 6.0 grams of sodium sulfite about 1.2 to 1.6 grams of hydroxylamine hydrochloride, about 3 to 10 grams of a paraphenylenediamine developing agent, about 0.03 to 1.0 gram of an antifoggant agent, about 0.002 gram of potassium iodide, sufficient water to make the solution 1 liter in volume and sufficient alkali to adjust the pH to about 10.8.
 9. A color photography developer bath for use in replenishing the developer bath of claim 8 when it is used in a roller transport apparatus, consisting of an aqueous solution, each liter of which comprises about 6.2 grams of sodium sulfite, about 1.6 grams of hydroxylamine hydrochloride, about 7.5 grams of a paraphenylenediamine developing agent, about 0.6 gram of an antifoggant agent, and sufficient alkali to adjust the pH to about 12.0.
 10. A photographic bleach-fix bath for use in color photographic film and print development consisting of an aqueous solution, each liter of which comprises about 120 grams ammonium thiosulphate, about 15 to 50 grams of an iron salt of ethylenediamine tetraacetic acid, and about 4 to 40 grams of an iron sequestering agent, and sufficient alkali and buffering agents to provide a pH of 6.4 to 7.0. 